I have a Mini Cooper R56 and I redid the timing hoping to solve a P0012 code error (code has been there forever). After I re-timed it putting the dummy tensioner at the appropriate ft-pounds and torquing the camshafts to the appropriate amount I went to put the top guide on and it didn't sit flush against the engine block. I went ahead and put the 2 bolts on the top guide and it sat flush after tightening it but there was quite a bit of pressure on it. Fast forward to this week I heard a weird rattle and pulled the valve cover. I noticed that the top guide has cracked. The guide probably had 12,000 miles on it at the time. Can someone tell me what I'm doing wrong? Should there be tension on the guide or does it just sit and gently push down the chain. I dont remember there being so much tension on the guide when I put it on last. (Side note: I had everything locked including the crankshaft)


Thank you so much. Daven

 

Maybe there was already a crack in the guide you didn't notice, that removing and reinstalling amplified or caused the plastic to shift somehow. Everything should be very tight and snug when reinstalled, but I don't recall noticing resistance when torquing down the top guide. You mentioned 12k miles on the top guide, is that the same for the rest of the cartridge, i.e. chain, guides, tensioner? Either way, does seem strange...

 

Thanks for the quick reply. It just seems like the chain is too tight somehow? To answer your question, yes everything was replaced brand new when the new timing chain was put on. Is it possible for the tensioner to somehow un-spring causing the tensioner to extend even further?

 

Should the top guide be installed before putting any tension on the chain? It's been awhile since doing this job.

 

I don't think that is possible. I really don't know how it would be too tight unless it somehow 'bunched up' on one of the sprockets and skipped a link in the chain or something if that's even possible... how much slack did you have without the tensioner or the tensioner tool in? And you're sure the lower guide locking pins and all that were correctly aligned?

And I've seen it done both ways, guide then tensioner, tensioner then guide. Didn't seem to make much difference. Hopefully someone else has some further insight here. I did it tensioner then guide last time and as previously mentioned did not notice any serious resistance.

 

 

 

I'm not seeing any photos/attachments

 

Yep, no pictures.

I had the same question when I re-assembled after replacing head gasket, including a whole new timing kit. The top piece engaged the chain before it bottomed out on the head, so tightening those two screws made it seem like it put some pressure on the chain. I went ahead and torqued it down and ran it like that. It sounded fine in that regard when it ran. I had to re-do all that work to replace rings as it turns out, but I assume I'll run into that again and it's OK.

There is pressured contact at pretty much all points of the plastic to chain as far as I can tell. Definitely on the tensioner side, at the top, and on the opposite side as well. I think that's just how it goes.

 

Glad someone else ran into this issue as well. I'm calling my local parts to place an order for a new top guide and I guess to see what happens. I tried to upload the pictures yet again. They're not really helpful but if you look closely you can see how it sits on the head.